1. Field of the Invention
The inventions disclosed herein generally relate to catalysts for dissociation of hydrogen, for example, catalysts used in fuel cells as electrodes for promoting the dissociation of electrons from hydrogen molecules and the association of electrons with protons.
2. Description of the Related Art
Fuel cells are presently used to convert hydrogen rich fuel into electricity without combusting the fuel. For example, methanol, propane, and similar fuels that are rich in hydrogen and/or pure hydrogen gas fuel cell systems have been developed which generate electricity from the migration of the hydrogen in those fuels across a membrane. Because these fuels are not burned, pollution from such fuel cells is quite low or non-existent.
These fuel cells are generally more than twice as efficient as gasoline engines because they run cooler without the need for insulation and structural reinforcement. Additionally, some fuels such as methanol, are relatively inexpensive.
A single “cell” of a hydrogen-type fuel cell system or “fuel cell stack” usually consists a single electrolyte sandwiched between electrodes. This sandwich is disposed between current collectors which usually serve as the poles (i.e., the anode and cathode) of the cell.
Such a fuel cell generates current by transforming or dissociating (usually by using the catalyst in the electrodes) hydrogen gas into a mixture of hydrogen ions and electrons with a catalyst on the anode side of the cell. Because of the insulating nature of the electrolyte, the ions transfer through the electrolyte to the cathode side of the cell while the electrons are conducted to the current collectors and through a load to do work. The electrons then travel to the cathode side current collector where they disperse onto the electrodes to combine with incoming hydrogen ions, oxygen, or air in the presence of a catalyst to form water completing the circuit. This process occurs in many types of fuel cells, including for example, but without limitation, alkaline, solid polymer, phosphoric acid and solid oxide fuel cells.
Recently, the solid polymer membrane fuel cell has become the focus of much attention. A broad spectrum of industries, including automotive and power utilities, are now developing solid polymer membrane fuel cells for use with hydrogen fuels.
The cost of certain components of the solid polymer membrane fuel cell systems, as well as other factors, has slowed the commercialization of these systems. For example, the cost of platinum used for the catalyst of the modern solid polymer membrane fuel cell remains as a barrier to the production of low cost fuel cell systems.